OK, we’ve heard of blog addicts, but this 23-year-old guy in San Francisco takes the cake.

Not content with plain old blogging and vlogging (that’s short for video blogging), 23-year-old Justin Kan is showing his life to the whole world via online video, 24 hours a day, seven times a week. It’s Justin.tv, and for now, people are watching.

Some people live blog. This guy is “lifecasting.” Justin put a camera on his head so that he can chronicle everything he does everyday — and I mean everything, including bathroom breaks.

The site promises that Justin will continue this Internet reality TV show until the day he dies: “Justin will wear the camera until the day he dies. By which we mean if he takes it off, we’ll kill him.”

Here’s an excerpt from an article in the San Francisco Chronicle:

Kan calls it “lifecasting.” The concept is simple: Using technology his team developed, Kan has strapped a camera to his head to capture every moment of his existence in live streaming video on the Internet. Viewers literally see the world through Kan’s virtual eyes, which broadcast his life onto the Web 24/7. He interacts with his audience through 21 chat rooms and hundreds of e-mails each day. He even took their calls on his cell phone until he got overwhelmed.

The show’s slogan says it all: “Waste time watching other people waste time.” And that’s what tens of thousand of folks around the globe are doing, turning Kan into an online phenom by tuning in to his irreverent and uncensored world. That sudden explosion of peeping onlookers has caused so many technical difficulties that Justin.tv had to recruit volunteers from the audience to keep the show rolling.

So, is this genius, or the ultimate expression of online narcissism? Probably both, as many ventures are in this brave new world of Web 2.0, reality TV, citizen journalism, social networking and user-generated content. On the one hand, we’d rather watch ordinary people like us, whether they’re doing ordinary or extraordinary things, and wonderful or stupid acts (as opposed, say, to professional TV hosts, actors and actresses doing unintentionally stupid things). On the other hand, maybe many of us are becoming increasingly self-absorbed, in the backlash against those days when Old Media shoved content we didn’t want down our throats.

I’m an optimist, however, so I believe it’s possible to strike the right balance. Instead of turning the whole world into our own personal versions of “The Truman Show.”